Ante-post favourites Bobs Worth and Silviniaco Conti head those remaining at the five-day stage.
The Willie Mullins-trained On His Own had been geared towards another crack at the Crabbie's Grand National but having won the Thyestes Chase he followed up with an easy success in the Bobbyjo Chase, prompting a rethink from connections.
Mullins said afterwards "he's just going out of handicaps and could win a really good race", nominating the Punchestown Gold Cup as an option.
As well as defending champion Bobs Worth, Nicky Henderson is represented by Hennessy hero Triolo D'Alene.
Paul Nicholls' Silviniaco Conti was still going well when falling three out in last year's renewal and advertised his chance in winning the King George VI Chase on Boxing Day, but the Ditcheat trainer has been forced to rule out Rocky Creek who is suffering from a bout of ringworm.
The eight-year-old, runner-up in the Hennessy and Argento Chase in his two outings this season, will now be aimed at the Grand National at Aintree next month.
Nicholls wrote in his exclusive Betfair column: "The good news is that it is treatable in time to re-route him to the Grand National once again, and we will now prepare him for Aintree.
"Of course, it is hugely frustrating as I thought he was going to Cheltenham with a live outside chance in the Gold Cup, but it is not an injury as such and we still have a big target to aim him at this season."
Philip Fenton's Irish Hennessy winner Last Instalment and the Mouse Morris-trained First Lieutenant add further strength to the raiding party from Ireland, with owners Gigginstown House Stud also having Tony Martin's Bog Warrior in the race.
Irish runners feature further in the shape of last year's RSA Chase winner Lord Windermere (Jim Culloty) and Lyreen Legend (Dessie Hughes).
Captain Chris represents Philip Hobbs, while Sue Smith has Cloudy Too and George Charlton fields Knockara Beau, who was the shock conqueror of Big Buck's in the Cleeve Hurdle in January.
The Giant Bolster has been fourth and second in the last two renewals and stands his ground for David Bridgwater, with Venetia Williams another double-handed through Houblon des Obeaux and Katenko.
Kim Bailey is praying for rain to boost the claims of Harry Topper and leading Crabbie's Grand National fancy Teaforthree is set to take his chance for Rebecca Curtis.
Bobs Worth remains favourite for the race, as well as Timeform top-rated, being available to back at 2.9215/8.